Systems And Methods For Venipuncture And Catheter Placement

ABSTRACT

Intravenous access is achieved by introducing a catheter having a guidewire safety tip at its distal end. The safety tip can be advanced and retracted using a slider disposed over an access needle which is initially present in the catheter. After the catheter has been properly positioned, the access needle and guidewire may be removed so that the catheter is available for use.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/167,149, filed Jan. 29, 2014, now U.S. Pat. No. 9,522,254, whichclaims priority to U.S. Provisional Patent Application No. 61/772,980,filed Mar. 5, 2013, and to U.S. Provisional Patent Application No.61/758,517, filed Jan. 30, 2013, each of which is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to methods and systems forperforming venipuncture. More particularly, the present inventionprovides a catheter and needle assembly with an integrated guidewire fortranscutaneous insertion of the catheter into a patient's vein.

The term “venipuncture” refers generally to the process of obtainingintravenous access for any one of a variety of purposes, includingintravenous infusion, therapy, blood sampling, and the like. In thehospital, for example, venipuncture is commonly used to place a smallintravenous catheter for delivering intravenous fluids, drug delivery,blood sampling and the like.

While venipuncture and intravenous access in relatively healthy patientscan be a simple matter, such access is often needed in patients who arenot healthy and may have small, tortuous, collapsed, fragile, and/ordifficult to locate veins. In such patients, venipuncture andintravenous access can be very challenging, particularly to lessexperienced phlebotomists, paramedics, nurses, and other health carepractitioners.

In addition to difficult access, many intravenous catheter placementsystems can result in accidental punctures and/or accidental needlecontamination during or after placement of the intravenous catheter.

A particularly effective intravenous catheter placement device isdescribed in commonly owned U.S. Patent Publ. 2008/0300574. This patentdescribes a catheter placement device which includes a handle havingmechanism for advancing a guidewire through an access needle whichcarries the catheter where the handle is adapted to automaticallyretract both the needle and the guidewire from the catheter after theplacement procedure is complete. While the catheter placement device hasan effective and valuable design, the need to employ a relativelycomplex deployment handle increases the device's cost and complexity.Additionally, the handle can obscure the presence and status of theneedle and guidewire components of the tool, thus making use of theinsertion tool less intuitive.

For these reasons, it would be desirable to provide improved methods,systems, and tools for deploying intravenous catheters using needles andguidewires. It would be particularly desirable to provide simplifieddeployment systems and assemblies having fewer components and, even moredesirably, to provide components which are clearly visible to the userand configured to be utilized and manipulated in a straightforward,intuitive manner. At least some of these objectives will be met by theinventions described below.

2. Description of the Background Art

Intravenous catheter insertion devices and methods are described in U.S.Pat. Nos. 5,704,914 and 5,800,395 and in commonly owned U.S. PatentPublications 2010/0094310; 2010/0210934; and 2012/0197200, the fulldisclosures of which are incorporated herein by reference.

SUMMARY OF THE INVENTION

The present invention provides improved methods, systems, and assembliesfor performing venipuncture, in particular for placing intravenouscatheters at a target location in a patient's vein. While the methods,systems, and assemblies will be particularly useful for placement ofperipheral venous catheters, such as by placement in a vein on a hand oran arm, they can also be useful with placement of a central venouscatheter by insertion into a central vein, such as the internal jugularvein on the neck or the subclavian vein on the chest. The methods,systems, and assemblies could, in some instances, even be useful withplacement of a catheter in a central or other artery, but such placementis not a principal purpose of the present invention.

An intravenous catheter assembly in accordance with the principles ofthe present invention comprises a tubular catheter body, an accessneedle, a guidewire, and a slide for deploying the guidewire. Thetubular catheter body has a distal end, a proximal end, and at least onelumen therebetween. The access needle has a tissue-penetrating distaltip and usually a lumen therethrough. In a first embodiment, theguidewire is disposed in the lumen of the access needle. In a secondembodiment, the guidewire is disposed outside of but in parallel to theaccess needle, typically riding in an axial groove formed in theexterior of the needle. In both embodiments, the guidewire has a distaltip configured to extend distally of the catheter to facilitateadvancement of the catheter in the vasculature, as will be described inmore detail below. The distal tip will frequently be in the form of asafety tip, such as a coiled safety tip as described in U.S. PatentPubl. 2008/0300574, the full disclosure which has previously beenincorporated herein by reference.

In a first embodiment, the slide of the catheter assembly is slidablydisposed over an exterior of a proximal region of the access needle andis coupled to a proximal end of the guidewire. In this way, theguidewire may be distally advanced by sliding the slide forwardly ordistally over the access needle in order to position the distal tip ofthe guidewire beyond the distal end of the catheter. Once in thisconfiguration, the access needle can be fully or partly retracted, orleft in place without retraction, and the catheter and the distallyprojecting guidewire can be advanced in tandem to position the distalend of the catheter body at a target site in the venous or othervasculature. By advancing the catheter and the projecting guidewire intandem, the guidewire acts as a “fixed” guidewire tip, furthersimplifying the catheter placement protocol of the present invention.The projecting wire will inhibit the distal tip of the catheter fromsticking or kinking on an internal wall of the blood vessel.

In a second embodiment, the catheter assembly further includes a housingattached to a proximal end of the access needle, where the slide isdisposed over the housing. The access needle is fixedly secured to adistal end of the housing, and the catheter is detachably secured to thedistal end of the housing. In this way, the slide can be used to advancethe guidewire beyond the distal ends of the catheter and the accessneedle, and the housing, access needle and guidewire may be detached andremoved from the catheter after the catheter is in place at a desiredlocation in the vein.

In a third embodiment, a proximal region of the catheter is disposedwithin the housing, and the proximal end of the catheter and a proximalend of the access needle may be configured to be engaged by the slide toadvance the catheter and needle in tandem with the guidewire relative tothe housing after the guidewire has been extended distally beyond thedistal end of the catheter.

Coupling the guidewire to the slide can be accomplished in any mannerwhich allows advancement or retraction of the slide to impart anequivalent advancement or retraction of the guidewire through the needlelumen. When the guidewire is disposed exteriorly of the access needle,the slide can be directly connected to a proximal end of the guidewirewith minimum interference from the access needle. When the guidewire isdisposed in the access needle lumen, then the coupling will need topenetrate the needle. For example, the slide and the guidewire could becoupled through a magnetic coupling which would not require any slot orpassage in the needle. Both the slide and a proximal portion of theguidewire could carry magnetic elements and the needle could be formedof a non-magnetic material, such as a non-magnetic stainless steel, andthe magnetic elements could couple through the wall of the needle. Moretypically, however, a slot or other axial passage will be formed in theneedle allowing the slide to be coupled to the guidewire by a physicallink which passes through the slot. In the illustrated embodiments, thelink is formed simply by bending a proximal end of the guidewire at anangle which allows it to pass through the slot and be embedded orotherwise attached to the slide.

As further shown in the illustrated embodiments, the slot on the accessneedle will usually be closed at both a distal and a proximal end todefine a specific length of travel through which the slider (and hencethe guidewire) can be advanced and retracted. Thus, the distance betweenthe two ends of the slot will define the maximum length of travel forthe guidewire.

In embodiments having a housing, a proximal end of the guidewire mayextend into the housing beyond the proximal end of the needle. Asdescribed above, a proximal end of the needle may be attached to adistal end of the housing and not extend into the housing. In suchcases, the slide can be coupled to the needle within the housing, andthe needle need not have a slot to allow such coupling. The needle, ofcourse, could extend within the interior of the housing and coupling tothe slide could be achieved as described previously for embodimentswithout housings.

The intravenous catheter assembly just described will preferably have atleast two configurations. In a first configuration, the distal tip ofthe access needle extends beyond the distal end of the catheter body bya distance in the range from 0.1 mm to 20 mm, preferably from 1 mm to 5mm. The distal tip of the guidewire remains retracted in the accessneedle, and the slider is retracted proximally from the proximal end ofthe proximal hub by a distance in the range from 10 mm to 100 mm,preferably from 15 mm to 35 mm. This first configuration is useful forinitially advancing the catheter and needle into a target vein with theguidewire retracted. In a second configuration, the distal tip of theaccess needle may be left in placed (extended beyond the catheter tip)or may be retracted, and the slide is advanced distally to the proximalend of the catheter body to, in turn, advance the distal tip of theguidewire distally of the distal end of the catheter body and/or accessneedle by a distance in the range from 5 mm to 100 mm, usually from 10mm to 35 mm. The access needle and guidewire will typically be capableof being withdrawn together from the catheter after the guidewire hasbeen advanced into the catheter body lumen.

In specific aspects of the present invention, the tubular catheter bodywill have a proximal hub with a hemostasis valve, optionally having aside tube. The access needle is adapted to slidably extend through thehemostasis valve so that the needle may be introduced into a target veinor other blood vessel with the hemostasis valve reducing the blood loss.In other preferred aspects, the slider will have a distal face whichmates with a proximal face of the proximal hub and/or the hemostasisvalve when the slider is fully advanced distally to extend theguidewire. Usually, the slider will detachably lock to the hub when thedistal face mates with the proximal face.

In another aspect of the present invention, a method for introducing anintravenous catheter to a target location in a vein of a patientcomprises penetrating a distal tip of an access needle which carries thecatheter into the vein. A guidewire is then advanced through a lumen ofthe needle by a short distance distally beyond a distal tip of thecatheter within the vein. After the guidewire has been advanced,typically through the lumen of the needle, the access needle may beretracted proximally (or not) leaving the guidewire in place. Theguidewire is optionally coupled to the catheter, and the guidewire andcatheter, and the guidewire and catheter then advanced in tandem(simultaneously) to position the distal tip of the catheter at thetarget location, preferably by holding the wings of the catheter hub.Once the catheter is properly located, the access needle and theguidewire are withdrawn completely from the catheter, leaving thecatheter in place for a desired medical protocol.

In specific aspects of the method, penetrating comprises penetratingboth the distal tip of the access needle and the distal end of thecatheter so that they lie in the vein prior to advancing the guidewire ashort distance distally beyond the distal tip of the guidewire.Advancing the guidewire typically comprises advancing a slider coupledto the guidewire over the access needle, usually coaxially over theaccess needle. The guidewire and the slider are coupled so thatadvancing the slider will in turn cause the guidewire to advance by alike distance. Of course, advancing the catheter will also advance theguidewire. Coupling may be achieved in any conventional manner asdescribed above. Coupling can be by direct attachment when the guidewireis exterior of the access needle. Alternatively, when the guidewire ispresent in the access needle lumen, the slider may be coupled to theguidewire magnetically or more usually by a link which travels through aslot formed in the needle. Typically, the slider engages the proximalhub after the slider is fully advanced in a distal direction and priorto advancing the guidewire and the catheter in tandem. When engaged, theslider may optionally be locked to the hub to help assure that theadvancement of the guidewire and catheter will be simultaneous and intandem. Any locking will usually be detachable but could be permanent orsemi-permanent since the slider and guidewire will usually be withdrawnand disposed of together with the access needle.

In alternative aspects of the methods of the present invention, aproximal region of the catheter may be disposed within a housing and theslide may be located on the housing and used to engage a proximal end ofthe catheter and a proximal end of the access needle to advance thecatheter and needle in tandem with the guidewire relative to the housingafter the guidewire has been extended distally beyond the distal end ofthe catheter. The slider may be used to fully advance the guidewirerelative to the access needle prior to advancing the guidewire, accessneedle and catheter in tandem.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 is a perspective view of an intravenous catheter and needleassembly constructed in accordance with the principles of the presentinvention.

FIG. 2 is an exploded view of the intravenous catheter and needleassembly of FIG. 1.

FIG. 3 is an axial cross-sectional view of the intravenous catheter andneedle assembly of FIGS. 1 and 2.

FIG. 3A is a cross-sectional view taken along line 3A-3A in FIG. 3.

FIG. 3B is an alternative cross-sectional view similar to that shown inFIG. 3A but showing the guidewire exterior to the access needle andtraveling in an axial groove formed in a wall of the access needle.

FIGS. 4A through 4D illustrate use of an intravenous catheter and needleassembly for introducing a catheter into a vein in accordance with theprinciples of the methods of the present invention.

FIG. 5 is a perspective view of a second embodiment of an intravenouscatheter and a needle assembly having a housing constructed inaccordance with the principles of the present invention.

FIGS. 6A-6C illustrate the intravenous catheter of FIG. 5 showing andaccess needle and a guidewire in different stages of advancement.

FIGS. 7A and 7B illustrate an alternate embodiment of the catheteradvancement mechanism of a catheter of FIG. 5.

FIG. 8 is a perspective view of third embodiment of an intravenouscatheter and needle assembly constructed in accordance with theprinciples of the present invention.

FIGS. 9A-9D illustrate the catheter of FIG. 8 showing the catheter,needle, and guidewire in various stages of advancement relative to ahandle.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-3, an exemplary intravenous catheter and needleassembly 10 constructed in accordance with the principles of the presentinvention comprises a catheter body 12 having a proximal end 14 and adistal end 16. A proximal hub 18 is attached to the proximal end 14 ofthe catheter body and includes a pair of attachment wings 20 which areused to secure the catheter hub to a patient's skin in the conventionalmanner after the catheter has been introduced into a target vein orother blood vessel.

The catheter body 12 has a central lumen 34 (FIG. 2) which slidablyreceives an access needle 22 having a tissue-penetrating distal tip 24which extends distally from the distal end 16 of the catheter body 12when the assembly is ready for use. The tissue-penetrating tip willusually be a sharpened needle-type or trocar-type tip but couldalternatively be a radiofrequency electrode or other energy-enhancedpenetrating element. A proximal grip 26 is attached to a proximal end ofthe needle 22 so that a user can grip and hold the needle as a slider 28is advanced over the needle, as will be described in more detail below.The slider 28 is attached to a proximal end of a guidewire 30 (FIG. 2),and the guidewire 30 usually has a safety tip 32 at its distal end,typically being a planar coil as illustrated. The proximal hub 18 willusually have a hemostasis valve 36 in its interior where the hemostasisvalve can receive the needle 22, as best seen in FIG. 3.

The slider 28 will be slidably mounted over the exterior of the needle22, as best seen in FIG. 3. The guidewire 30 will be present in acentral passage (not shown) of the access needle, and the slider 28 isslidably mounted over a proximal portion of the needle. A link 42attached to the slider 28 passes through a slot 38 in the proximalregion of the needle so that translation of the slider 28 in a distaldirection causes distal tip 32 of the guidewire to advance axially outthe distal tip 24 of the needle, as shown in broken line in FIG. 1,while retraction of the slider 28 and a proximal direction fullywithdraws the guidewire into the needle so that the guidewire is notvisible outside of the needle.

When the access needle 22 is introduced into the lumen 34 of thecatheter 12, as shown in FIG. 3, a distal seal 44 which is coaxiallydisposed over a distal portion of the needle seats at a distal end ofthe lumen 34 of the catheter to properly position the needle so that ashort distal segment, typically in the range from 0.1 mm to 20 mm,preferably from 1 mm to 5 mm, extends distally beyond the distal end 16of the catheter, as shown in FIG. 3. A blood perfusion port 46 is formedin the needle just proximally of the seal 44 so that blood entering thedistal tip 24 of the needle (when the needle is introduced to a vein orother blood vessel) will flow out through the port 46 and provide ablood flow to a visible region in the hub 18 or catheter body so that“flash back” occurs and the user knows that the needle has entered thevein. Blood will generally be contained within the hub 18 by thehemostasis valve 26.

Referring now to FIG. 3A, guidewire 30 will usually travel in lumen 31of the access needle 30. As an alternative, however, guidewire 30 couldtravel in an axial groove 33 formed in the wall of the access needle.

Referring now to FIGS. 4A through 4D, use of the intravenous catheterand needle assembly 10 for placing the catheter 12 within a vein V willbe described. The catheter needle assembly 10 is initially in its“shelf” configuration with the distal end 24 of the needle extendingdistally of the distal end 16 of the catheter body and the guidewire(not shown) fully retracted within the interior of the needle. The usercan manipulate the assembly by holding hub 18 and inserting the distaltip 24 of the needle through the patient's skin S into a desired vein Vuntil flash back is observed, as shown in FIG. 4A. Once flash back isobserved and it is confirmed that the needle tip is in the vein, thesafety tip 32 of the guidewire may be advanced by distally moving theslider 28 until a distal surface of the slider engages a proximalsurface of the hub, as shown in FIG. 4B. After the safety tip 32 hasbeen advanced, the needle can be partially or fully retracted (with fullretraction defined by the link 42 engaging a proximal end of slot 38),and the catheter 28 can be advanced in tandem with the needle safety tip32 limiting the risk of accidental perforation or other trauma. Thesafety tip 32 will be, in effect, locked in place by engagement of theslider 28 and the hub 18 so that the catheter 22 and safety tip areadvanced in tandem until the catheter tip 16 reaches a desired or targetlocation in the vein V, as shown in FIG. 4D. Once the distal end of thecatheter 16 is in its desired location, the sub-assembly of the needle22 and guidewire 30 may be fully withdrawn, as shown in FIG. 4D, and theproximal hub 18 secured to the patient's skin S, typically using theattachment wings 20 shown in FIG. 1. At this point, the catheter 22 andhub 18 are in place and ready for use in introducing fluids, takingsamples, introducing drugs, or any other desired purpose.

Referring now to FIGS. 5, 6A-6C, and 7A-7B, a second embodiment of acatheter and needle assembly 100 constructed in accordance with theprinciples of the present invention will be described. The catheter andneedle assembly 100 includes a catheter body 102 having a proximal end104, a distal end 106, and a proximal hub 108 attached to the proximalend. A pair of attachment wings 110 are secured to opposite sides of theproximal hub 108, and a housing 112 is detachably secured to a proximalend of the hub 108. The housing carries a slider 114, and the housingcan serve as a handle or manipulation tool for the catheter and needleassembly 100.

Referring now in particular to FIGS. 6A-6C, an access needle 118 extendsfrom a proximal end of the housing 112 and passes through a centrallumen of the catheter body 102. A distal tip 116 of the access needleextends distally just beyond the distal end of the catheter body 102,typically by distance of 1 mm to 10 mm, usually from 2 mm to 5 mm. Theaccess needle 118 slidably passes through a hemostasis valve 122, andthe proximal end of the needle 118 is fixedly secured to or within thehousing. In this way, the needle will remain stationary relative to thehousing when the catheter hub 108 is detached, as described in moredetail below.

A guidewire 120 is attached to the slider 114 via a pin 124 or othersuitable link or coupling number. The guidewire will typically have acoil or other safety tip, as best seen in FIG. 5. The guidewire tip isinitially held within a lumen of the access needle 118, as shown in FIG.6A. Once the slider 114 is partially advanced, as shown in FIG. 6B, thedistal tip of the guidewire 120 will emerge from the distal end of 116of the access needle 118. By further advancing the slider 114 in adistal direction, the guidewire 120 may be extended further, as shown inFIG. 6C.

As described with the prior embodiment, the guidewire 120 will typicallybe extended after the distal end 116 of the access needle 118 and thedistal end 106 of the catheter body 102 have been advanced into a veinand blood flashback observed. After the guidewire is extended by adesired length using the slider 114, the assembly of the guidewire,access needle, and catheter may be advanced simultaneously and in tandemwith the guidewire tip preventing the exposed needle tip 116 frominjuring the vein. Once the catheter is in the desired position, the hub108 may be detached from a distal end of the handle 112, as shown inbroken line in FIG. 6C. The needle and guidewire may then be withdrawnfrom the lumen of the catheter leaving the catheter in place forsubsequent use.

As shown in FIGS. 7A and 7B, a pair of engagement members 130 may beattached to the pin 124. Engagement members 130 could have a variety ofconfigurations, but for convenience they are shown as elongated rods.The engagement members 130 are aligned with a pair of holes 132 at thedistal end of the housing 112. Thus, as the slider 114 is initiallyadvanced, the engagement members will advance within the housing over apreselected length. When the slider 114 is advanced, for example abouthalf way through the housing as illustrated, the distal tips of theengagement members 130 will pass through the holes 132 and engage aproximal face of the hub 108. Thus, further advancement of theengagement members can detach the hub from the housing, as shown in FIG.7B.

Referring now to FIGS. 8 and 9A-9D, a third embodiment of a catheter andneedle assembly 150 and its use will be described. The catheter andneedle assembly 150 comprises a catheter having catheter body 152 with adistal end 154 and a proximal end 156 (best seen in FIGS. 9A-9B). Acatheter of 158 is attached to the proximal end 156 of the catheterbody, and a pair of attachment wings 160 are provided on the catheterhub, as generally described with the previous embodiments.

In contrast to the previous embodiments, the catheter hub 158 andproximal region of the catheter body 152 are received within an interiorof a housing 162. A slide 164 is mounted in a slot 174 on the housingand is attached to a proximal end of a guidewire 170 by a pin 172 othercoupling member so that distal advancement of the slide will cause thecatheter to advance distally from an undeployed configuration (where itis fully within an interior lumen of access needle 166, as shown in FIG.9A) to a deployed configuration (where it has advanced distally beyond adistal end of access needle 166, as shown in FIG. 9B).

The sequence of guidewire and catheter deployment is best understood byobserving the differences between FIGS. 9A and 9B. In FIG. 9A, both thecatheter 152 and the guidewire 170 are undeployed, and the catheterneedle assembly 150 is ready to be introduced into a vein of a patient.A user can manipulate the housing 162 as a handle and can access thepatient vein in a conventional manner, typically by observing bloodfeedback to confirm that the tip 168 of the needle 166 has entered thevein.

Once inside the vein, the user may hold the housing stationary andadvance the slider 164 sufficiently to deploy a tip, typically a safetytip of the guidewire 160, as shown in FIG. 9B. The user may thenmanipulate the housing to advance the catheter may with the guidewire170, needle 166, and catheter body 152 remaining stationary relative toeach other. The safety tip of the guidewire prevents the needle tip fromdamaging the vein.

In order to expose the entire length of the catheter body 152 forintroduction into the vein, the slider 164 will be fully advanced to thedistal direction within the slot 174, as shown in FIG. 9C. The assemblyincluding the housing 162, catheter body 152, access needle 166, andguidewire 170 may then be advanced until the distal end 154 of thecatheter reaches the desired location within the patient vein. At thatpoint, the housing may be pulled off the catheter and the hub 158released through the open end 176 of the housing. A proximal end of theneedle 166 will be secured in a sliding needle disc 178 so that theneedle remains attached to the housing 162 and the needle and guidewire117 may be removed together from the lumen of the catheter body 152,leaving the catheter in place ready for use.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. It is intended thatthe following claims define the scope of the invention and that methodsand structures within the scope of these claims and their equivalents becovered thereby.

What is claimed is:
 1. A method for introducing an catheter to a targetlocation in a vein of a patient, comprising: accessing the vein with adistal tip of a needle, the needle including a needle shaft surroundedby the catheter, the accessing comprising positioning a distal end ofthe catheter in the vein; advancing a coiled safety tip of a guidewirefrom within the needle into the vein through the distal tip of theneedle; moving the guidewire, needle, and catheter in tandem through thevein to position the distal tip of the catheter at the target location;and withdrawing the needle and the guidewire from the catheter.
 2. Themethod according to claim 1, wherein advancing the coiled safety tip ofthe guidewire comprises advancing a slider coupled to the guidewire overthe needle.
 3. The method according to claim 2, wherein a proximalregion of the catheter is disposed within a housing, and wherein theslide engages a proximal end of the catheter and a proximal end of theneedle to advance the catheter and needle in tandem with the guidewirerelative to the housing.
 4. The method according to claim 3, wherein theguidewire is fully advanced relative to the needle prior to advancingthe guidewire, needle and catheter in tandem.
 5. The method according toclaim 2, further comprising locking the slider to a hub of the catheter.6. The method according to claim 1, wherein the guidewire is advancedthrough a lumen of the needle.
 7. The method according to claim 1,wherein the guidewire is advanced through an axial groove formed in anexterior surface of the needle.
 8. The method according to claim 1,wherein advancing the coiled safety tip of the guidewire from within theneedle into the vein comprises extending the coiled safety tip beyondthe distal end of the catheter by a distance in a range from 5 mm to 100mm.